Jon Mark Hirshon, M.D., M.P.H., Board Certified in both Emergency Medicine and Preventive Medicine, seeks a Doctorate in Epidemiology in order to acquire advanced skills in linking, manipulating and analyzing large databases. The candidate's long-term goal is to develop emergency departments as significant sites for public health surveillance and hypothesis-driven research. The objective of this application is to analyze State of Maryland data to determine whether there is geographic variability in emergency department utilization for asthma within the State of Maryland. He then plans to develop a multiple variable model that incorporates socio-demographic variables and environmental factors to evaluate what risk modifiers impact the use of EDs for asthma. Since the need to seek emergent medical care is a sentinel event for individuals with asthma, a better understanding of variables associated with ED utilization will focus further population based research related to asthma exacerbations. The specific research aims are: 1) quantify rates of asthma-related ED visits by region; 2) quantify the degree to which the amount of utilization variability is an artifact of differences in hospital coding practices; 3) develop a model that incorporates environmental factors, such as criteria air pollutants per county, and socio-demographic variables, such as new housing construction, to evaluate the causes affecting the risk of using the ED for asthma. The linking of multiple statewide data sources to evaluate geographic variability in the need to seek emergent medical care for asthma has not been done. Maryland is a wonderful location to study population-based data due to: 1) the multiple statewide health care, environmental and socio-demographic databases; 2) the geographic and population variability mirroring the range of diversity seen within the United States; and 3) its relatively small size. This research will allow us to obtain a better understanding of the ED utilization differences seen within Maryland, while further evaluating these differences for specific environmental and socio-demographic modifiers. Considering its rich research resources, University of Maryland is an ideal environment to conduct this study. The research has potential nationwide applicability and could lead to innovative strategies to meet the Healthy People 2010 objective 24-3 focused on decreasing ED utilization for asthma.